Diabetes mellitus is a global public health challenge. Diabetes is a leading cause of disease burden worldwide [1] and is increasing in prevalence, with an estimated 422 million adults having diabetes in 2014 [2]. The cooccurrence of diabetes and depression is common, with the prevalence rates of depression and anxiety at least twice as high in patients with type 1 or type 2 diabetes compared to the general population worldwide [3-5]. Depression is associated with poor diabetes self-management [6,7] and increased disease severity, complications, and mortality [8,9]. Subthreshold depression (clinically significant symptoms of depression that do not meet diagnostic criteria for a major depressive episode or dysthymia) is more common in people with diabetes than major depression, with approximately half of all adults with type 2 diabetes experiencing at least one episode of subthreshold depression over five years [9]. Even subthreshold depression in diabetes is associated with poorer quality of life [10] and reduced adherence to diabetes self-care (including exercise, diet, and medication) [11], in addition to being a risk factor for future major depression [12].

Diabetes distress is a construct partly overlapping with depression in people with diabetes, and includes negative thoughts and emotions towards diabetes and its treatment [13]. Approximately 10-30% of people with diabetes experience severe diabetes distress [14,15], yet many of these people are not clinically depressed. Approximately 70% of people with type 2 diabetes display high levels of diabetes-related distress without meeting criteria for major depressive disorders [16,17]. Diabetes distress is associated with poor glycemic control, acting as a unique contributor to poor self-care adherence [18]. Diabetes distress is also a risk factor for the incidence and persistence of depressive symptoms [19].

Thus, international guidelines for diabetes management now recognize the importance of psychological care, not only to improve quality of life, but also diabetes self-management and medical outcomes [20]. Screening for both depression and diabetes distress, followed by appropriate interventions, has been recommended [21,22]. A stepped-care approach to the management of depression in people with diabetes has been suggested, with mild or subthreshold symptoms of depression managed within primary care, utilizing evidence-based self-help interventions [23]. This approach is in line with recommendations by the UK National Health Service, and Diabetes UK, for low-intensity psychological interventions to be used for people with diabetes with lower-level depression or distress [24].

Given the large numbers of people affected by diabetes globally, accessibility and cost-effectiveness are key issues in their psychological care. The Internet is an increasingly popular and cost-effective method of increasing access to evidence-based psychological interventions, and overcomes several of the traditional barriers to accessing mental health care, such as cost and concerns about stigma and privacy [25]. The Internet offers great potential for public health and prevention interventions [25]. For people with diabetes, Internet-based programs have demonstrated user acceptability and potential efficacy for improving diabetes self-management [26,27], and efficacy in reducing depression, anxiety, and diabetes distress [28-30]. Therefore, brief, Internet-based interventions have the potential to offer low-cost assistance to large numbers of people with diabetes who are experiencing mild or subthreshold psychological symptoms, as part of a stepped-care approach.

Therapeutic writing is a brief intervention that aims to improve physical or mental health [31]. The most common form of therapeutic writing is expressive writing (EW), in which thoughts and feelings regarding a stressful event are disclosed in writing, typically for 15-20 minutes for three to four days within a short period of time [32]. EW has been examined in over 250 studies investigating its effects on physical and/or mental health in a wide range of populations, including healthy participants, people with psychological problems, or people with long-term health conditions such as chronic pain, asthma, cancer, cystic fibrosis, or arthritis [31,33]. Mental health benefits of EW have included reduced symptoms of depression [34,35], anxiety [36], and posttraumatic stress [37,38]. Physical health benefits of EW have included improved lung function in asthma patients [39], improved immune function in patients with human immunodeficiency virus infection [40], and reduced fatigue and pain in adults with lupus or rheumatoid arthritis [41]. Evidence for behavioral change following EW also exists, such as decreased health care utilization [32,42], reduced aggression in adolescents [43], and improved exam performance [44]. Several reviews and meta-analyses of EW studies are available [31,33,39,45,46].

However, there are limitations to EW. Results of EW studies are quite variable, and effect sizes are often small. Meta-analyses of the effects of EW have found overall small effects of EW for distress (r=.102) [33] and physical health in medically ill populations (Cohen d=.21) [45]. The mechanisms of EW remain unclear [31], and tend to differ depending on the exact instructions that are used [47]. Furthermore, EW often involves an immediate increase in negative mood [31], even when followed by longer-term psychological benefits [46]. Thus, it has been suggested that EW in vulnerable populations is best undertaken with therapist support and follow-up [46].

Indeed, pilot trials of EW in people with diabetes have yielded mixed results. A pilot trial of 22 participants with type 1 diabetes randomized to either an EW group (instructed to write about an emotional or stressful topic related to diabetes for 20 minutes each day over four consecutive days) or a control group (instructed to write about factual topics related to diabetes) found that, at three-months follow-up, the EW group experienced less depressive symptoms and fewer incidences of physical illness [48]. The difference between the two groups in mean self-recorded blood glucose levels (effect size r=.236) was in the direction of benefit to the EW group, although this difference was not statistically significant [33]. However, a pilot trial of 41 adults with type 2 diabetes randomized to either EW or neutral writing found that EW was associated with a worsening in depressive symptoms, with no change in diabetes distress [49]. Of note, in the latter study the EW task involved writing about any stressful experience over the past month rather than a diabetes-specific task.

These findings have led researchers to investigate other variations of therapeutic writing, to maximize benefits and increase positive affect (and reduce distress) during the intervention. By modifying writing instructions, researchers can attempt to increase the likelihood that participants engage in desired cognitive processes, and thereby aim to increase the benefits gained from the writing task [38,47].

Benefit-finding writing involves participants writing about any positive thoughts and feelings about a stressful experience, such as an illness. Until recently, research has largely overlooked the utility of positively-focused writing following stressful events or illness [50]. However, there is emerging evidence that the experience of a medical illness often has sequelae that patients view as positive or beneficial [51]. Increased recognition has been given to the concept of benefit-finding, defined as, “identifying positive life changes resulting from adversity and negative life stressors, including illness” [52]. Correlated with posttraumatic growth (positive changes in individuals following traumatic life events) [53], benefit-finding has been associated with increased psychosocial wellbeing and decreased depression in a range of clinical populations [52,54], including people with diabetes [55]. Benefit-finding has also been linked with increased optimism, positive affect [56], self-efficacy, and adaptive coping strategies [57]. Benefit-finding in diabetes has been associated with lower symptoms of depression, increased adherence to diabetes self-care, and greater perceived coping effectiveness [55]. Furthermore, benefit-finding amongst parents of children with diabetes has also been associated with better glycemic control in their children [58]. It has therefore been suggested that interventions could be developed to increase benefit-finding in people with diabetes [55].

Benefit-finding writing aims to improve other outcomes by facilitating increased ongoing benefit-finding in relation to a medical condition or stressor. However, this concept has not yet been examined in people with diabetes. To date, benefit-finding writing has been examined in student and community samples [47,59-61], bereaved undergraduate students [62], participants who had recently experienced a relationship dissolution [50], breast cancer patients [42], and adults with lupus or rheumatoid arthritis [41].

Trials in nonclinical populations have found that benefit-finding writing results in less distress and increased positive affect immediately postwriting, compared to EW [60,61]. Benefit-finding writing is associated with greater increases in posttraumatic growth [47], and greater use of cognitive-insight words, compared to standard EW [61].

Two trials in clinical populations have compared benefit-finding writing with EW, with promising results [41,42]. In women with early-stage breast cancer, both benefit-finding and expressive-writing groups had significantly fewer medical appointments for cancer-related morbidities, relative to the control group [42]. In adults with lupus or rheumatoid arthritis, both benefit-finding writing and EW groups had lower fatigue at three months, relative to a control writing group [41]. An interaction with trait anxiety was also found; benefit-finding appeared to be more useful in reducing pain for those with high trait anxiety [41]. Furthermore, the authors noted that all 27 participants in the benefit-finding group were able to write some, “positive thoughts and feelings” about their illness experience [41]. Thus, the limited research on benefit-finding writing to date suggests that it may have the same longer-term health benefits as EW, but with the added advantage of immediate increases in positive affect

EW is a brief, low-cost intervention that can be delivered via the Internet [63-65]. These factors potentially make EW suitable as a short-term, low-intensity intervention to supplement treatment-as-usual for people with diabetes who have lower-level psychological needs [49]. While the results of pilot trials of EW in diabetes are mixed [48,49], benefit-finding writing is a more recent variation of therapeutic writing, which aims to facilitate increased perceptions of positive life changes resulting from adversity and negative life stressors. As outlined above, the limited research on benefit-finding writing suggests that it leads to increases in positive affect and posttraumatic growth, and may have the same physical health benefits as EW in populations with medical conditions. However, benefit-finding writing has not yet been examined in people with diabetes (type 1 or type 2).

Therefore, the current study aims to examine the feasibility and efficacy of an Internet-based benefit-finding writing (iBFW) intervention for adults with type 1 or type 2 diabetes. We seek to evaluate the efficacy of iBFW (compared to a control writing condition) in reducing diabetes distress and increasing benefit-finding in diabetes, and also in reducing symptoms of depression and anxiety, improving diabetes self-care and self-rated health, and improving health-care utilization. This paper presents the study protocol for this randomized controlled trial (RCT), using the online program Writing for Health.

Participants will be recruited online from Australian diabetes-related websites and publications, and from advertisements in waiting rooms of diabetes services and general practitioners (GPs) throughout Australia. Participants will apply for the study via the Writing for Health website [66], where they will complete an automated screening questionnaire (which also provides baseline data) after reading the study information and provide informed consent. Excluded applicants will immediately receive an onscreen message that informs them that the program is not suitable for them, and will provide links to appropriate resources. All potential participants will be provided with feedback on the severity of their depression and anxiety symptoms. Participants who meet eligibility criteria will proceed to online registration with the program, complete further online questionnaires (for further baseline data), be automatically randomized, and then complete the first writing session.

The inclusion and exclusion criteria and summarized in Textbox 1. Screening will be conducted online in the Writing for Health program. If any responses indicate ineligibility, screening will be automatically stopped and the next onscreen page will provide appropriate feedback (including links to relevant resources).

This study protocol has been approved by the Ethics Committee at St. Vincent’s Hospital, Sydney, which is certified by the National Health and Medical Research Council in Australia (HREC/13/SVH/379). This trial was prospectively registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12615000241538).

This RCT will be conducted using the online program Writing for Health [66], which was developed for this study by mental health researchers (including psychologists and a psychiatrist) at St. Vincent’s Hospital, Sydney, and the University of New South Wales. All stages of this study will be conducted online through Writing for Health, including information about the study, consent to participate, screening questionnaires with automated feedback, participant registration, randomization to one of two conditions, the writing intervention, and follow-up questionnaires. Automated reminder emails will be sent by Writing for Health to participants on each day of the intervention, and when it is time to complete their follow-up questionnaires.

Writing for Health provides minimal clinician assistance. Direct contact between participants and the clinicians will not occur in the standard course of the trial. Psychologists will monitor participant responses and distress levels throughout the intervention, and in accordance with the risk management protocol, will correspond with participants by email and phone to assess any support needed, and refer to appropriate services if required.

Participants registered with Writing for Health will be randomized to one of two conditions: iBFW or Internet-based use-of-time writing (control condition). Participants from both conditions will continue to receive usual care from their health services. Following randomization, both conditions involve participants writing online (in the Writing for Health program) for 15 minutes once a day, according to instructions provided. There will be three daily 15-minute online writing sessions (once per day for three consecutive days.) A timer on the screen counts down from 15 minutes, to allow participants to keep track of time during their writing session.

Information provided to participants in Writing for Health describes the aim of this study as investigating whether the writing exercises in the Writing for Health program improve the mental and physical wellbeing of people with diabetes. Participants will be informed that they will be randomized to one of two types of writing exercises, and both types of writing exercises will be described. However, research hypotheses will not be revealed.

Participants in the iBFW condition will be asked to write about any positive thoughts and feelings that they have had about their experiences with diabetes. The instructions (see Multimedia Appendix 1) are adapted from those used by Stanton and colleagues (2002) in benefit-finding writing for women with breast cancer [42]. The same instructions will be provided for all three of the writing sessions, consistent with previous studies of benefit-finding writing [41,42].

Participants in the control condition will be asked to write in detail about how their time was spent that day (first writing session) and plans for how their time will be spent the following day (second writing session) and week (third writing session). Participants will be instructed to be as objective as possible, and to focus on the facts and details of how their time was spent (or will be spent), and not to focus on their emotions or opinions. Writing about use-of-time is a neutral topic that has been previously used as an active control condition in a trial of EW, and was found to be associated with reduced physical and mental health symptoms [63].

The Diabetes Distress Scale (DDS17) [67] is a 17-item self-report measure of psychosocial stress associated with diabetes, with four reliable subscales: emotional burden (feeling overwhelmed by diabetes), physician-related distress (worries about access, trust, care), regime-related distress (concerns about diet, physical activity, medications), and interpersonal distress (not receiving understanding and appropriate support from others). Cut-off points on the DDS17 have been established for little or no distress, moderate distress, and high distress [68].

The 17-item Benefit Finding Scale [51] was developed to investigate benefit-finding in women with early stage breast cancer. In the current study, the stem question is modified from, “Having had breast cancer has…” to, “Having had diabetes has…” Participants are asked to respond to each of the 17 perceived benefits, such as, “has lead me to be more accepting of things” and, “has brought my family closer together” on a five-point scale with labels of not at all (1), a little (2), moderately (3), quite a bit (4), and extremely (5). This scale has previously been adapted for use in diabetes (with one item removed) and found to have one large factor and good internal consistency (Cronbach alpha=.89) in a population of adolescents with type 1 diabetes [55]. Table 1 provides an overview of all measurement tools and administration time-points.

The PHQ-9 [69] is a brief, widely used, reliable, and valid 9-item self-report that measures both the severity of depression over the preceding two weeks and diagnosis of depression based on criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4^thEdition (DSM-IV). This questionnaire has established cut-off scores of 5, 10, 15, and 20, representing mild, moderate, moderately severe, and severe depression. The total score ranges between 0 and 27, with scores equal or above 10 having a sensitivity of 88% and a specificity of 88% for major depression [69].

The GAD-7 [70] is a brief, widely used, reliable, and valid 7-item self-report that measures the severity of anxiety. Scores on the GAD-7 range from 0 to 21; scores of 5, 10, and 15 represent mild, moderate, and severe anxiety symptoms. A total score of 8 on the GAD-7 has been identified as an important threshold for identifying the presence of an anxiety disorder [71].

The International Positive and Negative Affect Schedule Short Form (I-PANAS-SF) [72] is a reliable and valid 10-item measure of positive and negative affect, which is comprised of 10 words that represent positive and negative affect. The correlations that this scale has with the positive and negative affect scales of the full 20-item form of the Positive and Negative Affect Schedule (PANAS) are .92 and .95, respectively [72]. Instructions were modified to assess state rather than trait affect, using the instructions of the 20-item PANAS-Immediate Version [73]. Participants will be instructed to indicate the degree of specific affect they feel, “right now, at the present moment”, on a scale of 1 to 5 (1=very slightly/not at all; 5=extremely).

The Summary of Diabetes Self-Care Activities Measure (Revised) [74] is an 11-item self-report measure of self-care of diabetes mellitus (including diet, exercise, blood sugar testing, foot care, and smoking) that is widely used both clinically and in research. Items in the revised version were selected based on their psychometric properties, sensitivity to change, and ease of scoring and interpretation [74]. In a critical appraisal of 26 different measures of diabetes outcomes, the Summary of Diabetes Self-Care Activities Measure (Revised) was one of only three measures to meet all criteria of suitability, validity, reliability, and sensitivity to change [75].

Self-rated health will be assessed by the question, “In general, how would you rate your health at present?” The five response options are very good, good, fair, poor, and very poor. Responses to this question have previously been found to be significantly associated with blood glucose indicator hemoglobin A1c (HbA1c; with poorer self-rated health associated with higher HbA1c levels) and number of self-reported diabetes-related symptoms in patients with type 2 diabetes [76].

Participants will be asked to answer the question, “In the past month, how many times have you visited a doctor or other health care professional?” This same question will be administered at three time-points: baseline, one-month follow-up, and three-month follow-up.

Immediately after each writing session, participants will be asked to rate how meaningful, personal, and distressing their writing exercise was, on a 7-point scale (0=not at all; 6=extremely). Similar questions have been used as manipulation checks in previous studies of therapeutic writing [42,77]. In addition, participants in the iBFW intervention condition will be asked immediately after each writing session if they were able to identify any positive thoughts or feelings about living with diabetes in their writing session.

A 12-item self-report questionnaire was developed to assess participants’ experiences and perceptions of the Writing for Health program. Item content was informed by self-report measures from other evaluations of Internet-based interventions. Items 1 to 6 ask participants to rate responses on a 5-point scale (from not at all to very) regarding aspects of usability and perceived helpfulness of the Writing for Health program, including how easy to use it was. Items 1 to 3 are taken from the Internet Intervention Evaluation Questionnaire [78]. Items 4 and 5 are modified from items previously used to assess credibility of writing interventions (asking participants to rate how logical the writing exercises seemed and how confident they would be in recommending it to a friend) [79]. Item 6 examined the perceived helpfulness of the writing exercises in reducing stress. Item 7 examined technical difficulties with the online program, and items 8-12 were open-ended questions examining the most helpful and least helpful aspects of the program, and any suggested improvements.